$(function () {
  var myChart = echarts.init(document.getElementById('main'));
  let xData = [],
    yData = [];
  xData.push(0);
  yData.push(0);
  for (let i = 0.1; i <= 1; i += 0.1) {
    xData.push(roundFractional(i, 1));
    yData.push(h(i));
  }
  function roundFractional(x, n) {
    return Math.round(x * Math.pow(10, n)) / Math.pow(10, n);
  }
  function h(p) {
    return -1 * p * Math.log2(p) - (1 - p) * Math.log2(1 - p);
  }
  // 指定图表的配置项和数据
  var option = {
    title: {
      text: 'ECharts 入门示例'
    },
    tooltip: {},
    legend: {
      data: ['H(x)']
    },
    xAxis: {
      data: xData
    },
    yAxis: {},
    series: [{
      name: '销量',
      type: 'line',
      smooth: true,
      data: yData
    }]
  };

  // 使用刚指定的配置项和数据显示图表。
  myChart.setOption(option);
});
